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Spiegel CJ, Mladenov N, Wall CB, Hollman K, Tran CH, Symons CC, Shurin JB. Life after a fiery death: Fire and plant biomass loading affect dissolved organic matter in experimental ponds. GLOBAL CHANGE BIOLOGY 2024; 30:e17061. [PMID: 38273537 DOI: 10.1111/gcb.17061] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 10/19/2023] [Accepted: 11/02/2023] [Indexed: 01/27/2024]
Abstract
Drier and hotter conditions linked with anthropogenic climate change can increase wildfire frequency and severity, influencing terrestrial and aquatic carbon cycles at broad spatial and temporal scales. The impacts of wildfire are complex and dependent on several factors that may increase terrestrial deposition and the influx of dissolved organic matter (DOM) from plants into nearby aquatic systems, resulting in the darkening of water color. We tested the effects of plant biomass quantity and its interaction with fire (burned vs. unburned plant biomass) on dissolved organic carbon (DOC) concentration and degradation (biological vs. photochemical) and DOM composition in 400 L freshwater ponds using a gradient experimental design. DOC concentration increased nonlinearly with plant biomass loading in both treatments, with overall higher concentrations (>56 mg/L) in the unburned treatment shortly after plant addition. We also observed nonlinear trends in fluorescence and UV-visible absorbance spectroscopic indices as a function of fire treatment and plant biomass, such as greater humification and specific UV absorbance at 254 nm (a proxy for aromatic DOM) over time. DOM humification occurred gradually over time with less humification in the burned treatment compared to the unburned treatment. Both burned and unburned biomass released noncolored, low molecular weight carbon compounds that were rapidly consumed by microbes. DOC decomposition exhibited a unimodal relationship with plant biomass, with microbes contributing more to DOC loss than photodegradation at intermediate biomass levels (100-300 g). Our findings demonstrate that the quantity of plant biomass leads to nonlinear responses in the dynamics and composition of DOM in experimental ponds that are altered by fire, indicating how disturbances interactively affect DOM processing and its role in aquatic environments.
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Affiliation(s)
- Cody J Spiegel
- Department of Ecology, Behavior and Evolution, School of Biological Sciences, University of California, San Diego, California, USA
| | - Natalie Mladenov
- Department of Civil, Construction and Environmental Engineering, San Diego State University, San Diego, California, USA
| | - Christopher B Wall
- Department of Ecology, Behavior and Evolution, School of Biological Sciences, University of California, San Diego, California, USA
| | - Kelly Hollman
- Department of Civil, Construction and Environmental Engineering, San Diego State University, San Diego, California, USA
| | - Cindy H Tran
- Department of Ecology, Behavior and Evolution, School of Biological Sciences, University of California, San Diego, California, USA
| | - Celia C Symons
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California, USA
| | - Jonathan B Shurin
- Department of Ecology, Behavior and Evolution, School of Biological Sciences, University of California, San Diego, California, USA
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2
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Rahman NEB, Smith SW, Lam WN, Chong KY, Chua MSE, Teo PY, Lee DWJ, Phua SY, Aw CY, Lee JSH, Wardle DA. Leaf decomposition and flammability are largely decoupled across species in a tropical swamp forest despite sharing some predictive leaf functional traits. THE NEW PHYTOLOGIST 2023; 238:598-611. [PMID: 36651117 DOI: 10.1111/nph.18742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 01/09/2023] [Indexed: 06/17/2023]
Abstract
Decomposition and fire are major carbon pathways in many ecosystems, yet potential linkages between these processes are poorly understood. We test whether variability in decomposability and flammability across species are related to each other and to key plant functional traits in tropical swamp forests, where habitat degradation is elevating decomposition and fire regimes. Using senesced and fresh leaves of 22 swamp tree species in Singapore, we conducted an in situ decomposition experiment and a laboratory flammability experiment. We analysed 16 leaf physical and biochemical traits as predictors of decomposability and components of flammability: combustibility, ignitability and sustainability. Decomposability and flammability were largely decoupled across species, despite some shared predictive traits such as specific leaf area (SLA). Physical traits predicted that thicker leaves with a smaller SLA and volume decomposed faster, while various cation concentrations predicted flammability components, particularly ignitability. We show that flammability and decomposability of swamp forest leaves are decoupled because flammability is mostly driven by biochemical traits, while decomposition is driven by physical traits. Our approach identifies species that are slow to decompose and burn (e.g. Calophyllum tetrapterum and Xanthophyllum flavescens), which could be planted to mitigate carbon losses in tropical swamp reforestation.
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Affiliation(s)
- Nur E B Rahman
- Asian School of the Environment, Nanyang Technological University, 62 Nanyang Drive, Singapore City, 637459, Singapore
| | - Stuart W Smith
- Asian School of the Environment, Nanyang Technological University, 62 Nanyang Drive, Singapore City, 637459, Singapore
- Ecology, Conservation and Zoonosis Research and Enterprise Group, School of Applied Sciences, University of Brighton, Lewes Road, Brighton, BN2 4GJ, UK
| | - Weng Ngai Lam
- Asian School of the Environment, Nanyang Technological University, 62 Nanyang Drive, Singapore City, 637459, Singapore
| | - Kwek Yan Chong
- Department of Biological Sciences, National University of Singapore, Science Drive 4, Singapore City, 117558, Singapore
- Singapore Botanic Gardens, National Parks Board, 1 Cluny Road, Singapore City, 259 569, Singapore
| | - Matthias S E Chua
- Asian School of the Environment, Nanyang Technological University, 62 Nanyang Drive, Singapore City, 637459, Singapore
- Department of Biological Sciences, National University of Singapore, Science Drive 4, Singapore City, 117558, Singapore
| | - Pei Yun Teo
- Asian School of the Environment, Nanyang Technological University, 62 Nanyang Drive, Singapore City, 637459, Singapore
| | - Daniel W J Lee
- Asian School of the Environment, Nanyang Technological University, 62 Nanyang Drive, Singapore City, 637459, Singapore
| | - Shi Yu Phua
- Asian School of the Environment, Nanyang Technological University, 62 Nanyang Drive, Singapore City, 637459, Singapore
| | - Cheryl Y Aw
- Asian School of the Environment, Nanyang Technological University, 62 Nanyang Drive, Singapore City, 637459, Singapore
| | - Janice S H Lee
- Asian School of the Environment, Nanyang Technological University, 62 Nanyang Drive, Singapore City, 637459, Singapore
| | - David A Wardle
- Asian School of the Environment, Nanyang Technological University, 62 Nanyang Drive, Singapore City, 637459, Singapore
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3
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Adams MA, Neumann M. Litter accumulation and fire risks show direct and indirect climate-dependence at continental scale. Nat Commun 2023; 14:1515. [PMID: 36934100 PMCID: PMC10024763 DOI: 10.1038/s41467-023-37166-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 03/03/2023] [Indexed: 03/20/2023] Open
Abstract
Litter decomposition / accumulation are rate limiting steps in soil formation, carbon sequestration, nutrient cycling and fire risk in temperate forests, highlighting the importance of robust predictive models at all geographic scales. Using a data set for the Australian continent, we show that among a range of models, >60% of the variance in litter mass over a 40-year time span can be accounted for by a parsimonious model with elapsed time, and indices of aridity and litter quality, as independent drivers. Aridity is an important driver of variation across large geographic and climatic ranges while litter quality shows emergent properties of climate-dependence. Up to 90% of variance in litter mass for individual forest types can be explained using models of identical structure. Results provide guidance for future decomposition studies. Algorithms reported here can significantly improve accuracy and reliability of predictions of carbon and nutrient dynamics and fire risk.
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Affiliation(s)
- Mark A Adams
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, Victoria, Australia.
| | - Mathias Neumann
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, Victoria, Australia
- Institute of Silviculture, Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences, Vienna, Austria
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4
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Pan Y, Cieraad E, Armstrong J, Armstrong W, Clarkson BR, Pedersen O, Visser EJW, Voesenek LACJ, van Bodegom PM. Leading trait dimensions in flood-tolerant plants. ANNALS OF BOTANY 2022; 130:383-392. [PMID: 35259242 PMCID: PMC9486907 DOI: 10.1093/aob/mcac031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 03/04/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND AIMS While trait-based approaches have provided critical insights into general plant functioning, we lack a comprehensive quantitative view on plant strategies in flooded conditions. Plants adapted to flooded conditions have specific traits (e.g. root porosity, low root/shoot ratio and shoot elongation) to cope with the environmental stressors including anoxic sediments, and the subsequent presence of phytotoxic compounds. In flooded habitats, plants also respond to potential nutrient and light limitations, e.g. through the expression of leaf economics traits and size-related traits, respectively. However, we do not know whether and how these trait dimensions are connected. METHODS Based on a trait dataset compiled on 131 plant species from 141 studies in flooded habitats, we quantitatively analysed how flooding-induced traits are positioned in relation to the other two dominant trait dimensions: leaf economics traits and size-related traits. We evaluated how these key trait components are expressed along wetness gradients, across habitat types and among plant life forms. KEY RESULTS We found that flooding-induced traits constitute a trait dimension independent from leaf economics traits and size-related traits, indicating that there is no generic trade-off associated with flooding adaptations. Moreover, individual flooding-induced traits themselves are to a large extent decoupled from each other. These results suggest that adaptation to stressful environments, such as flooding, can be stressor specific without generic adverse effects on plant functioning (e.g. causing trade-offs on leaf economics traits). CONCLUSIONS The trait expression across multiple dimensions promotes plant adaptations and coexistence across multifaceted flooded environments. The decoupled trait dimensions, as related to different environmental drivers, also explain why ecosystem functioning (including, for example, methane emissions) are species and habitat specific. Thus, our results provide a backbone for applying trait-based approaches in wetland ecology by considering flooding-induced traits as an independent trait dimension.
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Affiliation(s)
| | - Ellen Cieraad
- Institute of Environmental Sciences (CML), Leiden University, Leiden, The Netherlands
- Nelson Marlborough Institute of Technology, Nelson, New Zealand
| | - Jean Armstrong
- Department of Biological Sciences, University of Hull, Hull, UK
- School of Agriculture and Environment, The University of Western Australia, Perth, Australia
| | - William Armstrong
- Department of Biological Sciences, University of Hull, Hull, UK
- School of Agriculture and Environment, The University of Western Australia, Perth, Australia
| | | | - Ole Pedersen
- School of Agriculture and Environment, The University of Western Australia, Perth, Australia
- Freshwater Biological Laboratory, University of Copenhagen, Copenhagen, Denmark
| | - Eric J W Visser
- Experimental Plant Ecology, Institute for Water and Wetland Research, Radboud University, Nijmegen, The Netherlands
| | | | - Peter M van Bodegom
- Institute of Environmental Sciences (CML), Leiden University, Leiden, The Netherlands
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5
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Guo C, Yan ER, Cornelissen JHC. Size matters for linking traits to ecosystem multifunctionality. Trends Ecol Evol 2022; 37:803-813. [PMID: 35810137 DOI: 10.1016/j.tree.2022.06.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 05/20/2022] [Accepted: 06/08/2022] [Indexed: 10/17/2022]
Abstract
A priority research field addresses how to optimize diverse ecosystem services to people, including biodiversity support, regulatory, utilitarian and cultural services. This field may benefit from linking ecosystem services to the sizes of different body parts of organisms, with functional traits as the go-between. Using woody ecosystems to explore such linkages, we hypothesize that across stem diameter classes from trunk via branches to twigs, key wood and bark functional traits (especially those defining size-shape and resource economics spectra) vary both within individual trees and shrubs and across woody species, thereby together boosting ecosystem multifunctionality. While we focus on woody plants aboveground, we discuss promising extensions to belowground organs of trees and shrubs and analogs with other organisms, for example, vertebrate animals.
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Affiliation(s)
- Chao Guo
- Putuo Island Ecosystem Research Station, Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, and Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China; Institute of Eco-Chongming (IEC), 3663 North Zhongshan Road, Shanghai 200062, China
| | - En-Rong Yan
- Putuo Island Ecosystem Research Station, Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, and Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China; Institute of Eco-Chongming (IEC), 3663 North Zhongshan Road, Shanghai 200062, China.
| | - J Hans C Cornelissen
- Systems Ecology, A-Life, Faculty of Science, Vrije Universiteit (VU University), De Boelelaan 1085, 1081, HV, Amsterdam, The Netherlands
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6
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The Effects of Fire Disturbance on Litter Decomposition and C:N:P Stoichiometry in a Larix gmelinii Forest Ecosystem of Boreal China. FORESTS 2022. [DOI: 10.3390/f13071029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Fire disturbance can affect the function of the boreal forest ecosystem through litter decomposition and nutrient element return. In this study, we selected the Larix gmelinii forest, a typical forest ecosystem in boreal China, to explore the effect of different years (3 years, 9 years, 28 years) after high burn severity fire disturbance on the decomposition rate (k) of leaf litter and the Carbon:Nitrogen:Phosphorus (C:N:P) stoichiometry characteristics. Our results indicated that compared with the unburned control stands, the k increased by 91–109% within 9 years after fire disturbance, but 28 years after fire disturbance the decomposition rate of the upper litter decreased by 45% compared with the unburned control stands. After fire disturbance, litter decomposition in boreal forests can be promoted in the short term (e.g., 9 years after a fire) and inhibited in the long term (e.g., 28 years after a fire). Changes in litter nutrient elements caused by the effect of fire disturbance on litter decomposition and on the C, N, and C:N of litter were the main litter stoichiometry factors for litter decomposition 28 years after fire disturbance. The findings of this research characterize the long-term dynamic change of litter decomposition in the boreal forest ecosystem, providing data and theoretical support for further exploring the relationship between fire and litter decomposition.
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7
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Simpson KJ, Archibald S, Osborne CP. Savanna fire regimes depend on grass trait diversity. Trends Ecol Evol 2022; 37:749-758. [PMID: 35577616 DOI: 10.1016/j.tree.2022.04.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 04/14/2022] [Accepted: 04/20/2022] [Indexed: 11/17/2022]
Abstract
Grasses fuel most fires on Earth and strongly influence local fire behaviour through traits that determine how flammable they are. Therefore, grass communities that differ in their species and trait compositions give rise to significant spatial variation in savanna fire regimes across the world, which cannot be otherwise explained. Likewise, fire regimes are continuously modified by alterations to savanna grass community traits, through species introductions and climatic changes. However, current representation of grassy fuels in global fire models misses important variation and therefore limits predictive power. The inclusion of grass trait diversity in models, using remotely sensed trait proxies, for example, will greatly improve our ability to understand and project savanna fires and their roles in the Earth system.
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Affiliation(s)
- Kimberley J Simpson
- Plants, Photosynthesis and Soil, School of Biosciences, University of Sheffield, Sheffield, UK; Department of Botany, Rhodes University, Makhanda, South Africa.
| | - Sally Archibald
- Centre for African Ecology, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Colin P Osborne
- Plants, Photosynthesis and Soil, School of Biosciences, University of Sheffield, Sheffield, UK.
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8
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Bokhorst S, Cornelissen JHC, Veraverbeke S. Long-term legacies of seasonal extremes in Arctic ecosystem functioning. GLOBAL CHANGE BIOLOGY 2022; 28:3161-3162. [PMID: 35007375 DOI: 10.1111/gcb.16078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/05/2022] [Accepted: 01/05/2022] [Indexed: 06/14/2023]
Affiliation(s)
- Stef Bokhorst
- Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | | | - Sander Veraverbeke
- Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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9
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Zylstra P, Liow LH. Linking fire behaviour and its ecological effects to plant traits, using FRaME in R. Methods Ecol Evol 2021. [DOI: 10.1111/2041-210x.13615] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Philip Zylstra
- Centre for Sustainable Ecosystem Solutions University of Wollongong Wollongong NSW Australia
| | - Lee Hsiang Liow
- Centre for Sustainable Ecosystem Solutions University of Wollongong Wollongong NSW Australia
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10
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A simple method for estimation of leaf dry matter content in fresh leaves using leaf scattering albedo. Glob Ecol Conserv 2020. [DOI: 10.1016/j.gecco.2020.e01201] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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11
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Hopkins JR, Huffman JM, Platt WJ, Sikes BA. Frequent fire slows microbial decomposition of newly deposited fine fuels in a pyrophilic ecosystem. Oecologia 2020; 193:631-643. [PMID: 32699992 DOI: 10.1007/s00442-020-04699-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 06/25/2020] [Indexed: 11/25/2022]
Abstract
Frequent fires maintain nearly 50% of terrestrial ecosystems, and drive ecosystem changes that govern future fires. Since fires are dependent on available plant or fine fuels, ecosystem processes that alter fine fuel loads like microbial decomposition are particularly important and could modify future fires. We hypothesized that variation in short-term fire history would influence fuel dynamics in such ecosystems. We predicted that frequent fires within a short-time period would slow microbial decomposition of new fine fuels. We expected that fire effects would differ based on dominant substrates and that fire history would also alter soil nutrient availability, indirectly slowing decomposition. We measured decomposition of newly deposited fine fuels in a Longleaf pine savanna, comparing plots that burned 0, 1, 2, or 3 times between 2014 and 2016, and which were located in either close proximity to or away from overstory pines (Longleaf pine, Pinus palustris). Microbial decomposition was slower in plots near longleaf pines and, as the numbers of fires increased, decomposition slowed. We then used structural equation modeling to assess pathways for these effects (number of fires, 2016 fuel/fire characteristics, and soil chemistry). Increased fire frequency was directly associated with decreased microbial decomposition. While increased fires decreased nutrient availability, changes in nutrients were not associated with decomposition. Our findings indicate that increasing numbers of fires over short-time intervals can slow microbial decomposition of newly deposited fine fuels. This could favor fine fuel accumulation and drive positive feedbacks on future fires.
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Affiliation(s)
- Jacob R Hopkins
- Ecology and Evolutionary Biology, University of Kansas, 2101 Constant Avenue Takeru Higuchi Hall, Lawrence, KS, 66047, USA.
| | - Jean M Huffman
- Department of Biological Sciences, Louisiana State University, Baton Rouge, USA
| | - William J Platt
- Department of Biological Sciences, Louisiana State University, Baton Rouge, USA
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12
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Abstract
Globally, fire regimes are being altered by changing climatic conditions. New fire regimes have the potential to drive species extinctions and cause ecosystem state changes, with a range of consequences for ecosystem services. Despite the co-occurrence of forest fires with drought, current approaches to modelling flammability largely overlook the large body of research into plant vulnerability to drought. Here, we outline the mechanisms through which plant responses to drought may affect forest flammability, specifically fuel moisture and the ratio of dead to live fuels. We present a framework for modelling live fuel moisture content (moisture content of foliage and twigs) from soil water content and plant traits, including rooting patterns and leaf traits such as the turgor loss point, osmotic potential, elasticity and leaf mass per area. We also present evidence that physiological drought stress may contribute to previously observed fuel moisture thresholds in south-eastern Australia. Of particular relevance is leaf cavitation and subsequent shedding, which transforms live fuels into dead fuels, which are drier, and thus easier to ignite. We suggest that capitalising on drought research to inform wildfire research presents a major opportunity to develop new insights into wildfires, and new predictive models of seasonal fuel dynamics.
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13
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Fujii S, Berg MP, Cornelissen JHC. Living Litter: Dynamic Trait Spectra Predict Fauna Composition. Trends Ecol Evol 2020; 35:886-896. [PMID: 32522377 DOI: 10.1016/j.tree.2020.05.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 05/12/2020] [Accepted: 05/18/2020] [Indexed: 11/18/2022]
Abstract
Understanding what drives soil fauna species composition through space and time is crucial because we should preserve soil fauna biodiversity and its key role in ecosystem functioning in this era of fast environmental change. As plant leaf litter provides both food and habitat for soil fauna, a focus on litter traits that relate to these two functions will help in understanding soil invertebrate community structure and dynamics comprehensively. To advance this agenda, we propose a conceptual framework to explicitly link the invertebrate community composition to the temporal dynamics of the litter trait space defined by two axes: a food-quality axis related to plant resource economics and chemistry and a habitat-quality axis related to litter particle size and shape.
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Affiliation(s)
- Saori Fujii
- Department of Ecological Science, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands; Department of Forest Entomology, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba 305-8687, Japan.
| | - Matty P Berg
- Department of Ecological Science, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands; Conservation and Community Ecology Group, Groningen Institute for Evolutionary Life Sciences, Groningen University, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Johannes H C Cornelissen
- Department of Ecological Science, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
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14
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Pausas JG, Bond WJ. On the Three Major Recycling Pathways in Terrestrial Ecosystems. Trends Ecol Evol 2020; 35:767-775. [PMID: 32381268 DOI: 10.1016/j.tree.2020.04.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 04/03/2020] [Accepted: 04/09/2020] [Indexed: 12/27/2022]
Abstract
Plants are the largest biomass component of most terrestrial ecosystems, and litter decomposition is considered the dominant process by which nutrients return to plants. We show that in terrestrial ecosystems, there are three major pathways by which plant biomass is degraded into forms that release nutrients again available to plants: microbial decomposition; vertebrate herbivory; and wildfires. These processes act at different spatial and temporal scales, have different niches, and generates different ecological and evolutionary feedbacks. This holistic view in which microbes, herbivores, and wildfires play a joint role in the functioning of ecosystems contributes to a better understanding of the diversity of mechanisms regulating the biosphere.
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Affiliation(s)
- Juli G Pausas
- Centro de Investigaciones sobre Desertificación (CIDE-CSIC), Valencia, Spain.
| | - William J Bond
- Department of Biological Sciences, University of Cape Town, Cape Town, South Africa; South African Environmental Observation Network, National Research Foundation, Claremont, South Africa
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15
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Do relationships between leaf traits and fire behaviour of leaf litter beds persist in time? PLoS One 2018; 13:e0209780. [PMID: 30586427 PMCID: PMC6306239 DOI: 10.1371/journal.pone.0209780] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 12/11/2018] [Indexed: 11/28/2022] Open
Abstract
Wildland fires are a dominant disturbance on Earth. On the local scale, fire activity is also influenced by species-specific fire behaviour of leaf litter beds. Thus, researchers strive to identify plant functional traits governing fire behaviour. The currently accepted relationships between morphological characteristics of the individual particles, fuel bed structure and resulting fire behaviour have been established on freshly constructed leaf litter beds. To investigate to what degree these relationships are altered upon exposure of constructed leaf litter beds to outside weather conditions, a novel testing system was designed. It enables outdoor exposure of the constructed litter beds, their subsequent retrieval and fire behaviour testing without disturbing the sample structure. Two treatments were applied on seven monospecific leaf litters. “Fresh treatment” corresponded to the common practice of testing fire behaviour directly after fuel bed construction. In the “settled treatment” constructed fuel beds were exposed for 30 days to outside weather conditions before being tested. The “settled treatment” was designed to address physical changes in the fuel bed structure which occur due to repeated wetting of the fuel bed. Thus, to minimise the effects of decomposition and fragmentation, winter exposure was chosen. Within the “fresh treatment” previously established relationships between size, curl, bulk density and fire behaviour characteristics could be confirmed. In the “settled treatment” the majority of these relationships lost their significance. The “settled treatment” had significantly lower bulk density (BD), rate of spread, maximum flame height and maximum sand temperature at 1 cm depth; and significantly higher flaming duration and amount of unburned residues compared to the “fresh treatment”. Species with low initial BD were more affected by the treatment than species with high initial BD. The abrupt change in the fire behaviour of some leaf litter beds and the loss of numerous relationships between morphological characteristics of the individual particles and fire behaviour characteristics upon settled treatment indicate that fast occurring changes in the fuel bed structure should be taken into consideration if we are to understand the relationships between functional traits and local fire activity.
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16
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Smith SW, Speed JDM, Bukombe J, Hassan SN, Lyamuya RD, Mtweve PJ, Sundsdal A, Graae BJ. Litter type and termites regulate root decomposition across contrasting savanna land‐uses. OIKOS 2018. [DOI: 10.1111/oik.05697] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Stuart W. Smith
- Dept of Biology, Norwegian Univ. of Science and Technology NO‐7491 Trondheim Norway
| | - James D. M. Speed
- NTNU Univ. Museum, Norwegian Univ. of Science and Technology Trondheim Norway
| | - John Bukombe
- Tanzania Wildlife Research Inst. Arusha Tanzania
| | - Shombe N. Hassan
- Sokoine Univ. of Agriculture, College of Forestry, Wildlife and Tourism – Wildlife Management Dept Morogoro Tanzania
| | | | - Philipo Jacob Mtweve
- Sokoine Univ. of Agriculture, College of Forestry, Wildlife and Tourism – Wildlife Management Dept Morogoro Tanzania
| | - Anders Sundsdal
- Dept of Biology, Norwegian Univ. of Science and Technology NO‐7491 Trondheim Norway
| | - Bente J. Graae
- Dept of Biology, Norwegian Univ. of Science and Technology NO‐7491 Trondheim Norway
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